Fix NSID (or OPT option code 3)

dns.go

@@ -230,6 +230,11 @@ func zoneMatch(pattern, zone string) (ok bool) {
 
 // DnameLength returns the length of a packed dname.
 func DomainNameLength(s string) int { // TODO better name
+        // Special case for '.'
+        if s == "." {
+                return 1
+        }
+
 	// Add trailing dot to canonicalize name.
 	if n := len(s); n == 0 || s[n-1] != '.' {
 		return n + 1

msg.go

@@ -320,18 +320,13 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
                                 // Length of the entire option section
 				for j := 0; j < val.Field(i).Len(); j++ {
 					element := val.Field(i).Index(j)
-					code := uint16(element.Field(0).Uint())
 					// for each code we should do something else
 					h, e := hex.DecodeString(string(element.Field(1).String()))
 					if e != nil {
 						//fmt.Fprintf(os.Stderr, "dns: failure packing OTP")
 						return lenmsg, false
 					}
-					// Option Code
-                                        // the rdlength needs to be set somehow
-                                        println("code ", code)
-                                        println("length ", len(string(h)))
-                                        println("off ", off)
+					code := uint16(element.Field(0).Uint())
 					msg[off], msg[off+1] = packUint16(code)
 					// Length
 					msg[off+2], msg[off+3] = packUint16(uint16(len(string(h))))

rawmsg.go

@@ -4,17 +4,14 @@
 
 package dns
 
-/* Function defined in this subpackage work on []byte and but still
- * provide some higher level functions
- */
-
+// Function defined in this subpackage work on []byte and but still
+// provide some higher level functions.
 
 // SetRdlength sets the length of the length of the rdata
 // directly at the correct position in the buffer buf.
 // If buf does not look like a DNS message false is returned,
 // otherwise true.
 func (h *RR_Header) RawSetRdlength(buf []byte, off int) bool {
-        // TODO double check DomainNameLength
 	off1 := DomainNameLength(h.Name)
 	if off1 == 0 || len(buf) < off+off1+2+2+4+1 {
 		return false